1. Field of the Invention
The present invention relates to a vacuum pump.
2. Description of the Prior Art
State of the Art (DE 20 2005 019 644 U1) discloses a vacuum pump, e.g., a turbomolecular pump having a rotor with rotatable pump active components and mounted on a rotor shaft. The rotatable pump active components cooperate with stationary pump active components, so-called stator.
The above-mentioned state of the art discloses securing of a bell-shaped rotor to an end side of a rotor shaft with a screw. To this end, the rotor shaft is provided with a recess in which the rotor journal engages.
The drawback of the embodiment disclosed in the state of the art consists in that the rotor can rotate relative to the rotor shaft because the connection of the rotor with the rotor shaft is essentially based on a frictional connection. Because of this, a relative rotation can occur in case of overload. The overload leads to loosening of the connection so that the security of the screw connection is not insured.
Loosening of the rotor during operation leads to a total damage of the pump. Prior art (WO 2012/077411 A1) discloses means for preventing rotation of the rotor. According to this state of the art, there is provided a formlocking connection at which the rotor is secured to the end side of the rotor shaft with several screws. This prevents rotation of the rotor relative to the rotor shaft and, thus, disengagement of the rotor from the rotor shaft. However, the drawback of this state-of-the-art embodiment consists in that the mounting of the rotor is rather expensive and a number of high-cost components, screws, is necessary which make the pump more costly.
The object of the invention is to provide a vacuum pump in which the above-discussed drawbacks of the prior art solutions are absent.